📖 Book
✓ Link checked
Paid
Beginner
Why we picked it
The single best thing ever written on customer conversations. It teaches you to ask about the customer's life and past behaviour, not your idea, so you can't be lied to. If a founder reads one thing before talking to a single customer, it's this.
From
momtestbook.com
by Rob Fitzpatrick
~130 pages
- Talk about their life, not your idea.
- Ask about specifics in the past, not opinions about the future.
- 'That's so cool, I'd totally buy it' is a compliment, not data, dig for commitment and evidence.
Open
momtestbook.com →
✍️ Essay
✓ Link checked
Free
Beginner
Why we picked it
The definitive essay on where good ideas come from: notice problems you personally have, don't force it. Use it as the lens for judging whether your idea is a real problem or a solution in search of one.
From
paulgraham.com
by Paul Graham
~20 min read
- Live in the future and build what's missing.
- The best ideas look like bad ideas at first (schleps and hard-to-explain).
- Start with problems you have, in a domain you actually know.
Open
paulgraham.com →
📄 Article
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Freemium
Beginner
Why we picked it
Todd Jackson studied how dozens of now-large companies validated their very first idea. The pattern that repeats: deliver the outcome by hand, talk to real users, and watch for genuine emotion. A polite 'that's cool' is a no. Strong reactions are the signal you want.
From
Lenny's Newsletter
by Todd Jackson
~15 min read
- Manual delivery beats a survey for early signal.
- Look for strong emotion, not politeness.
- Great ideas usually start from a problem you have lived.
Open
lennysnewsletter.com →
📖 Book
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Paid
Beginner
Why we picked it
Savoia, who led early Google AdWords, argues most ideas fail because nobody wanted them, and teaches pretotyping: cheap experiments that generate your own data on real demand before you build. You get concrete tactics like the fake-door and the mechanical-turk test, plus a way to demand skin-in-the-game commitment rather than opinions. Practical for anyone who wants a test that can prove them wrong.
From
Alberto Savoia
by Alberto Savoia
~250 pages
- Collect your own data on real behaviour instead of trusting opinions
- Pretotype the idea to test demand before you build a prototype
- Measure commitments like a signup or a payment, not verbal enthusiasm
Open
albertosavoia.com →
📖 Book
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Paid
Intermediate
Why we picked it
This is the practical, step-by-step manual for the Lean Startup ideas, built around the one-page Lean Canvas and a system for ranking your riskiest assumptions. It gives you a repeatable way to decide what to test next instead of guessing, which is exactly the 'what must I learn next' question at the heart of a good MVP. Use it when you want a process rather than inspiration.
From
LeanFoundry
by Ash Maurya
240 pages
- Map your whole idea on one page, then attack the riskiest box first
- Prioritise experiments by risk, not by what is easiest or most fun to build
- Talk to customers on a schedule, treating each conversation as data
Open
leanfoundry.com →
📄 Article
✓ Link checked
Freemium
Beginner
Why we picked it
Sometimes the two ideas are a proxy for a deeper problem: you have no agreed way to make a call when you disagree. This HBR piece treats disagreement as a skill and pushes you to set decision rules in advance, including who gets the final say on which kinds of calls, so a single stuck choice does not calcify into resentment. It is short and pairs well with a disagree and commit rule: back one idea for a defined window with pre-agreed metrics, then review.
From
Harvard Business Review
by Evelyn Nam
~8 min read
- Decide ahead of time who owns which decisions, so a deadlock has a built-in tiebreaker instead of grinding to a halt.
- Commit to one direction for a set period with clear metrics, then revisit, rather than relitigating it every week.
- Unresolved founder conflict is a leading reason startups fail, so treating this as urgent is warranted, not dramatic.
Open
hbr.org →
📄 Article
✓ Link checked
Free
Intermediate
Why we picked it
This is the guide for the check-in itself: what to actually say when you sit down. Perel names the three things co-founder fights are secretly about (power, closeness, recognition) so you stop arguing about the surface and address the real thing directly. Her concrete rules (keep an argument under 10 seconds then pause, swap 'always/never' for 'in this moment it feels like', address one problem at a time, never assassinate character) are exactly the disagreement-muscle drills you run when stakes are low so they hold when stakes are high.
From
First Round Review
by Esther Perel (via First Round Review)
20 min read
- Most co-founder fights are misdiagnosed: they are about power, recognition, or feeling sidelined, not the strategy you are nominally arguing over, so say 'I feel sidelined' instead of blaming.
- Fight cleanly with mechanical rules: one issue at a time, arguments capped at ten seconds before a pause, no 'always/never', acknowledge and validate before you rebut.
- Proactive maintenance beats crisis repair; keep a running list of what you appreciate in your co-founder and consider a coach as a neutral third party for accountability.
Open
review.firstround.com →
✍️ Essay
✓ Link checked
Free
Intermediate
Why we picked it
This is the cleanest map of the three ways co-founders actually decide things: consensus, functional expertise (your domain, your call), and CEO tie-break. Batista's sharp point is that early co-founders sit at near-zero hierarchical distance, so nobody wants to pull rank, and that awkwardness is exactly why fights fester. It gives you the language to agree up front which mode applies where, so overlap stops being a turf war.
From
edbatista.com
by Ed Batista
12 min read
- Name the three decision modes explicitly (consensus, domain expertise, CEO authority) and agree which one governs which call before you need it
- Consensus is the trap: leaning on it for everything produces circular arguments and paralysis, not harmony
- The CEO must learn to influence rather than command, and the other founder must genuinely disagree and commit, not silently resent
Open
edbatista.com →
📖 Book
✓ Link checked
Paid
Intermediate
Why we picked it
Choosing between two ideas is a bet under uncertainty, and Duke gives you the mindset for it: judge the decision by its process, not by how it happens to turn out. She shows how to ask how sure am I and what evidence would change my mind, which lowers the ego stakes between co-founders. It helps you both hold ideas loosely enough to follow the data.
From
Annie Duke
by Annie Duke
~272 pages
- Judge decisions by process, not just by the outcome
- Ask how confident you are and what would change your mind
- Framing choices as bets reduces ego and defensiveness
Open
amazon.com →
📄 Article
✓ Link checked
Free
Intermediate
Why we picked it
This is the framework for acting decisively without certainty. Duke, a former pro poker player, teaches founders to judge the quality of the decision, not the outcome (she calls the trap "resulting"), and to shrink every call to its smallest, most reversible version: "Is there a way for me to make this a smaller decision than the one I am considering?" That is exactly how you stop needing to know how it all ends and just make the next move.
From
First Round Review
by Annie Duke (via First Round Review)
~20 min read
- Separate decision quality from outcomes: a good process can still get an unlucky result, so stop grading yourself only on how things turned out
- Every decision is a bet on an unknown future, so make your reasoning explicit rather than trusting gut feel
- Shrink the horizon: ask "what's the smallest, cheapest, most reversible version of this?" so low-stakes calls move fast and only truly irreversible ones get deliberation
Open
review.firstround.com →
📄 Article
✓ Link checked
Free
Intermediate
Why we picked it
Turns the vague feeling of product-market fit into a number you can move. Ask users how they would feel if they could no longer use the product, then track the share who say 'very disappointed'. Under 40 percent means keep working. A test you can run on an idea long before you scale it.
From
First Round Review
by Rahul Vohra
~20 min read
- The 40 percent 'very disappointed' benchmark for product-market fit.
- Segment to your high-expectation customers and build for them.
- Make the fit score a metric you improve quarter by quarter.
Open
review.firstround.com →
📄 Article
✓ Link checked
Freemium
Intermediate
Why we picked it
Once you are testing an idea, this piece gives you concrete signals that tell you whether it is actually working, from retention curves to organic word of mouth. It collects how experienced founders and investors describe the moment an idea starts to land. Read it so you know what evidence to look for instead of guessing whether the idea is good.
From
Lenny's Newsletter
by Lenny Rachitsky
about 15 min read
- Retention that flattens rather than falling to zero is the clearest signal
- Organic growth and referrals show the problem was real
- If people would be very disappointed to lose it, you are onto something
Open
lennysnewsletter.com →
Why we picked it
The book that gave the world 'MVP', 'build-measure-learn', and 'validated learning'. It reframes a startup as a series of experiments, not a bet, the mental model everything else in this category builds on.
From
theleanstartup.com
by Eric Ries
~330 pages
- Progress = validated learning, not features shipped.
- Build the minimum that produces a real learning loop.
- Decide pivot-or-persevere on evidence, on a schedule.
Open
theleanstartup.com →
